In clean rooms where semiconductors, magnetic storage media, or thin film circuits are produced and in clean rooms where pharmaceuticals are produced, similar cleaning problems are encountered. Frequently, it is necessary to clean a metal, glass, or plastic surface so as to remove metal and other particulates, and so as to remove organic and other residues. As an example, after a metal pipe has been installed in a clean room, it is necessary to clean the interior surface of the metal pipe so as to remove metal particles resulting from prior manufacturing, cutting, or facing operations.
Known methods for cleaning metal, glass, or plastic surfaces in clean rooms have employed polyester filamentary wipers, as exemplified in Paley et al. U.S. Pat. No. 4,888,229, or polyvinyl alcohol or polyvinyl acetal rollers, as exemplified in Tomita et al. U.S. Pat. No. 4,566,911. Cotton wipers and other filamentary wipers have been also employed, as well as other cleaning articles of diverse materials, such as sponges and swabs.
Commonly, in clean rooms, metal, glass, or plastic tubes of small interior diameters are installed. A known method for cleaning the interior surface of such a tube in a clean room has comprised cutting a small piece from a wiper, wadding the cut piece, and blowing the wadded piece through the tube by means of compressed air.
on a larger scale, plugs made of polyurethane foam or other polymeric foam have been used to clean the interior surfaces of pipe lines of large interior diameters, as exemplified in Wheaton U.S. Pat. No. 2,906,650, Knapp U.S. Pat. No. 3,277,508, and Knapp U.S. Pat. No. 5,032,185 . Plugs of related interest are exemplified in Bitter U.S. Pat. No. 3,119,600 and Hamrick U.S. Pat. No. 3,120,947.
Ideally, articles for cleaning metal, glass, or plastic surfaces in clean rooms should satisfy certain criteria. Such articles should he hydrophilic and static-dissipative. Particularly but not exclusively if used in clean rooms where semiconductors, magnetic storage media, or thin film circuits are produced, such articles should have very low counts of potentially destructive particles released in deionized water, particularly particles of a size greater than about 0.5 .mu.m, and very low counts of potentially deleteterious ions released in deionized water, particularly chloride, fluoride, sodium, sulfate, sulfite or silicon ions. Heretofore, none of the wipers, rollers, or other cleaning articles available for cleaning metal, glass, or plastic surfaces in clean rooms have satisfied all of these criteria.